According to White, Whittaker (20-4 MMA, 11-2 UFC) started to complain of pain in his abdomen late last night and was taken to the hospital. His injury isn't believed to be related to his weight cut.

The unfortunate turn of events is a huge blow for Whittaker, a New Zealand-born Australian who was set to headline Saturday night's pay-per-view at Rob Laver Arena in Melbourne. A middleweight bout between Israel Adesanya vs. Anderson Silva is the new main event.

It's the second Australian headliner that Whittaker has been forced to miss. Last February, he cited a multitude of injuries in withdrawing from a scheduled title fight vs. Luke Rockhold, which was set to headline UFC 221 in Perth. Yoel Romero stepped in and defeated Rockhold to earn a rematch vs. Whittaker, which Whittaker won last June by split decision in a "Fight of the Year" candidate.

Whittaker won the interim middleweight title at UFC 213 in July 2017 with a unanimous decision against Romero. Whittaker was named the undisputed champion after Georges St-Pierre vacated the belt later that year. Whittaker has yet to defend his belt after Romero missed weight for their rematch.